Test Step 7. Check the Operation of the ECM by Creating Open and Short Circuits at the ECM Connector

283

TM 9-2320-312-24-2

Troubleshooting Section

B. Disconnect ECM engine harness connector

Expected Result:

J1/P1. Thoroughly inspect both halves of the

A short circuit diagnostic code is active when the

connector J1/P1 for signs of corrosion or

jumper is installed. An open circuit diagnostic code

moisture. Reconnect engine harness connector

is active when the jumper is removed.

J1/P1.

C. Turn the ignition key switch to the ON position.

Results:

Monitor the "Active Diagnostic Code" screen.

OK The engine harness and the ECM are OK.

Wait at least 15 seconds for activation of the

code.

Repair: Perform the following repair:

An open circuit diagnostic code should be active

for the suspect sensor.

1. Temporarily connect the suspect sensor.

D. Turn the ignition key switch to the OFF position.

2. If the diagnostic code remains active, replace

the sensor.

E. Disconnect ECM engine harness connector

J1/P1. Install a breakout T.

3. Ensure that the diagnostic code is no longer

active.

F. Fabricate a jumper wire 150 mm (6 inch) long.

Crimp a Deutsch Socket to both ends of the wire.

4. Verify that the repair eliminates the problem.

G. Install the jumper wire on the breakout T.

STOP.

Insert the jumper wire between the terminal for

Not OK The open circuit diagnostic code

the suspect sensor supply and the common

connection for the sensor.

remains active when the jumper is installed. The

most probable location for the open is in the

A short circuit diagnostic code should be active

sensor common or in the sensor supply in the

when the jumper wire is installed.

vehicle harness between the ECM and the sensor.

Remove the jumper. Proceed to Test Step 7.

Refer to Illustration 116 for the breakout T.

Test Step 7. Check the Operation of the

ECM by Creating Open and Short Circuits

Expected Result:

at the ECM Connector.

Open circuit diagnostic codes and short circuit

diagnostic codes were active.

Results:

OK The ECM is operating properly. Proceed

to Test Step 8.

Not OK One of the following conditions exists:

The open circuit diagnostic code is not active

when the harness is disconnected. The short

circuit diagnostic code is not active when the

jumper wire is installed.

Repair: Perform the following repair:

1. Temporarily connect a test ECM.

2. Remove all jumpers and replace all connectors.

3. Recheck the system for active diagnostic

codes.

g00846127

Illustration 116

Breakout T

4. Repeat the Test Step.

A. Turn the ignition key switch to the OFF position.

5. If the problem is resolved with the test ECM,

reconnect the suspect ECM.